The present invention generally relates to buckles for seat belts and more particularly to that type of buckle usable with a buckle pretensioner or belt tightener.
The present invention relates to a new and improved buckle for use with a buckle pretensioner of a safety belt system and one which resists the very high g-forces generated when the pretensioner is activated. As known in the art, these g-forces arise as the pretensioner is rapidly moved to remove belt slack about an occupant. At the end of a pretensioning stroke the buckle frame (typically attached to the pretensioner) is suddenly stopped, however, due to inertia, the button will continue to move relative to the now stopped buckle frame. This movement of the button, unless compensated may cause, in certain situations, the latch plate of the buckle to move out of its locked position, permitting the tongue to unlatch.
An object of the present invention is to overcome the above deficiency in the prior art.
Accordingly, the invention comprises: a seat belt buckle operable with a pretensioner connected thereto for moving the buckle a determinable distance to remove slack of the seat belt about an occupant, the buckle comprising: a frame, adapted to be connected to the pretensioner, defining a tongue receiving opening to receive a tongue as the tongue is moved in a first direction, the frame having a first latch opening therein, and opposing frame sides, each side including a latch plate slot arranged generally perpendicular to the first direction. A weight assembly pivotably connected to the frame to generate a line contact force upon the top of the latch plate during operation of the pretensioner forces the latch plate into the latch opening. A manually moveable button is operatively received upon the frame having ramps for lifting the latch plate to its unlatched position. A second embodiment of the invention provides a supplemental button blocking surface on the weight to interact with the button. Another embodiment of the invention is directed to a means for generating a frictional retarding force on the button.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.